1. Field of the Invention.
The present invention relates to marking data, specifically patient identification data, in the permanent emulsion of medical x-ray images, particularly mammograms.
2. Discussion of the Relevant Art.
It is a long-standing trend in radiology to positively place patient identification data in the permanent emulsion of any obtained patient x-ray. Pertinent patient identification data normally includes information such as the patient's name, medical record number, date, location, and identification of the equipment upon which the x-ray is obtained. Failure to properly and permanently identify medical x-rays may, at best, cause such unlabeled x-rays to be become misplaced, misidentified to the patient, or unidentified to the patient--resulting in a requirement for patient re-exposure to x-rays. At worst, an improperly identified or unidentified x-ray might result in misadministration of a therapeutic procedure to the wrong portion of the proper patient, or to the wrong patient.
Due to the requirement for permanent, positive identification of medical x-rays, techniques such as affixing stickers to the obtained x-rays or writing by hand on the x-ray films are generally considered unacceptable. Such techniques are implicitly non-permanent and allow for error by the radiological technologist in improperly identifying films. There is a small possibility, albeit remote, of improperly changing the patient's name or other patient data by accident or artifice subsequent to an initial labeling. Delays, howsoever minute, between the generation of an x-ray image and transcription of data thereon may result in confusion causing an erroneous affixation of information to a particular x-ray image. Although part of the high skills and extensive training of a radiological technologist is explicitly directed to the elmination of error in the identification of x-ray images, errors will inevitably occur. Any large medical facility, such as a hospital, which generates vast numbers of x-rays incur errors in its x-ray identifications in proportion to the strength and refinement of its x-ray identification procedures as well as in proportion to the diligence of its x-ray technologist personnel.
Because of the obvious requirement for positive patient identification in the permanent image of medical x-rays, it has long been the prevailing procedure to selectively block portions of an x-ray film exposed by the standard film-screen technique in order to later place patient identification data within these selectively blocked portions. The patient identification data thus appears within the permanent image of the developed x-ray film. Particularly in the prior procedure, an x-ray film or cassette used in the standard film-screen x-ray technique contains a small region, normally rectangular in shape, which is initially covered by a lead blocker. When the x-ray film or cassette is exposed with an anatomical image, the area under the lead blocker is shielded from the x-ray beam and thereby not exposed. The still undeveloped x-ray film cassette is then inserted (in room light) into an "identification camera" such as the X-Omatic device made by the Kodak Corporation. This identification camera automatically slides the lead blocker from that region where it had previously occluded an area of the x-ray film during radiology, thereby allowing selective exposure of that area of the film. Next, a flash card, which is simply a modified index card preferably having a glossy finish onto which patient identification data and other desired data has been previously typed, is also inserted into the "identification camera". The "identification camera" subsequently flashes this data onto the previously unexposed area of the x-ray film, exposing the film with the data image. The entire x-ray film is then developed in a routine fashion, therein permanently capturing both the patient anatomical image and the patient identification data in one step.
Astoundingly, this standard radiological practice is not used in mammography, which is one of the most prevalent of all x-rays utilized in the developed countries. The reason that the usual x-ray identification procedure is not used in mammography is that the standard mammography cassette is made of thin plastic and is too fragile to permit the use of a sliding lead blocker. For lack of a standard system, data labeling of mammograms has haphazardly transpired by diverse techniques. In the production of an x-ray film mammogram, some radiology centers flash the patient data onto the x-ray film at a time and a location normally remote from the original radiological exposure of the mammogram, using darkroom devices such as the Kodak Model B. This method requires contact with the x-ray film by the human hand, risking fingerprints. Any fingerprints which result from the direct film handling show up as troublesome artifacts on the developed x-ray image, potentially causing erroneous x-ray interpretation. There additionally exists risk in the possible confusion, and misidentification, of films within the darkroom. The darkroom method for emplacing identification data on mammograms is furthermore cumbersome, labor intensive, and protracted in time and space.
In xeromammography, another popular form of mammography, there is even less ability to properly label the x-ray film with appropriate patient data. Some facilities producing xeromammograms attempt to label them during the initial exposure by using plastic alpha-numeric letters and numbers. These small and numerous plastic artifacts are difficult and time consuming to handle, are frequently misarrayed, misaligned or lost, and do not create a pleasing or professional image on the developed xeroradiographs. In response to the difficulties in emplacing patient identification within the image field of both film-mammograms and xeromammograms, the majority of mammographers simply affix a pressure-sensitive patient identification sticker after each mammogram film exposure is fully processed. Some mammographers even enter patient data on the back of the processed xeromammogram with pencil. The gap in time, and often in space, between the initial x-ray mammography of the patient and the later labeling of the mammogram is conducive to error at a degree which has long since ceased to be tolerated in the production of conventional, film-screen technique, medical x-rays.
The present invention specially addresses these above-referenced deficiencies in the art and is concerned with positive patient data identification marking within the image field of medical x-rays, and particularly on mammograms of both the film and xeromammography types.